Video Systems
A video system includes Displays, Sensors, Signal Processors, Image/Video Stores, and Control Interfaces, as well as in some cases an Internet connection. The subject of this disclosure is local-site transport (LST), which locally interconnects video system equipment. Video equipment serves local environments. LST operating within environments occupied by people is distinguished from telecommunications, which interconnects remotely located equipment. Internet servers provide the content and manage the interactive experiences which are presented to consumers via video systems in any location connected to the Internet. That is why video systems are an intrinsic aspect of every delivery system for pixel-rich information.
Infrastructure Video Systems Versus Mobile Video Systems
There are two kinds of video systems: Mobile and Infrastructure. These two types of system differ from one another in two ways: 1) Mobile systems are monolithic, whereas Infrastructure systems are assembled by customers or their agents from disparately manufactured equipment, and 2) Mobile systems draw power from batteries, whereas Infrastructure systems draw power from mains electricity. To summarize:                Mobile video systems draw power from batteries and are typically monolithic, each assembled by a single manufacturer from various components. For example, a smart phone implements a video processor, which reads multiple cameras and drives a palm-size screen, all packed within one enclosure.        Infrastructure video systems are powered by mains electricity and are assembled by customers from equipment that is produced by various manufacturers.        
Both kinds of video systems are important for creating and accessing Internet content. Nevertheless, these two kinds of video systems present starkly different engineering challenges.
Mobile video systems are more readily integrated into a person's everyday life than Infrastructure video systems, due to portability.
Infrastructure video systems generate experiences that are more immersive than their Mobile counterparts because of the ability of immersive Virtual Reality (iVR™) to surround us with Displays and Sensors while drawing potentially large amounts of electrical power for arbitrarily long durations.
Example applications of Mobile video systems include                Collecting/posting Social Media material        Augmented Reality (AR) games, such as Pokémon GO        Virtual Reality (VR) systems wherein displays and/or cameras are tethered to a portable Media Processing Unit (MPU), which might itself be a smart phone or another portable device        
Example applications of Infrastructure video systems include                Video surveillance        Machine vision        Motor vehicle safety (sometimes related to machine vision)        Retail signage        Shopper behavior analysis (sometimes related to machine vision)        Motor vehicle driver and passenger navigation, control, and entertainment        Home Entertainment        immersive Virtual Reality (“iVR”), wherein cameras monitor the subject and displays surround the subject, such that the video system captures and presents pixel information from all angles        
Examples of Infrastructure video equipment include desktop (or tower) PCs, PC monitors, set-top boxes, TVs, video surveillance cameras, video surveillance recorders, video surveillance monitors, vehicle navigation and safety cameras, vehicle electrical control units (ECUs), automotive control & navigation displays, automotive entertainment cameras, automotive entertainment displays, retail and kiosk displays, iVR cameras, and iVR displays. The Infrastructure video equipment market sector is large and growing fast.
By contrast, there is no Mobile video equipment market. All of the components within a Mobile video system (the Internet Interface, digital Processor, Camera(s), and Display(s)) operate in close proximity, such that the entire system can be worn or carried. The interconnections operate over short ranges under well-controlled conditions, and all of the components are supplied as a monolithic entity, such that the customer has no choices to make.
Infrastructure video systems, by contrast, place great demands on video interconnections. Infrastructure video equipment is mounted at arbitrary locations within a building or campus, and the video is carried over a diversity of physical pathways including metal cables, radio, and/or optical fibre between independently manufactured equipment.
Video Local-Site Transports (LSTs)
This disclosure addresses one aspect of Infrastructure video system implementation: Local-Site Transport (LST). An LST conveys a video signal over an electromagnetic (EM) propagation pathway from a sending piece of equipment to a receiving piece of equipment located as far as hundreds of meters away from the sending equipment.
Three examples of electromagnetic (EM) pathways include electricity over wires, radiation through the air, and photons through a fibre. LSTs represent the transported video as EM energy in a form appropriate to the medium, for example voltage, radio waves, or light.
Types of Signal
For the purposes of this disclosure, a signal is a variable, conveyed as EM energy whose amplitude changes over time.
Two attributes characterize every signal:                Time                    Continuous: The time between values is limited by the resolution at which it is possible to measure time            Discrete (“Sampled”): The time between values is predetermined, and its inverse is the sampled signal's “sampling rate”                        Amplitude                    Continuous: The number of possible values is limited by the resolution at which it is possible to measure energy            Discrete (“Quantized”): The number of possible values is predetermined, and its logarithm base 2 is the quantized signal's “number of bits”                        
There are four combinations of these attributes and thus four distinct types of signal:                “Analog” signals are continuous-time, continuous-amplitude signals.        “Digital” signals are discrete-time, discrete-amplitude signals.        “Pulsatile” signals are discrete-time, continuous-amplitude signals. There is an appropriation of this unusual meaning of the term “pulsatile” for clarity in this disclosure. Pulsatile signals are commonly processed with “sampled analog” circuits, while others also skilled in the art might prefer the term “sample-and-hold” circuits.        “Neuronal” signals are continuous-time, discrete-amplitude signals. This is not necessarily the usual meaning of the word “neuronal,” but is fitting for this fourth quadrant of the taxonomy. Neuronal signals are outside the scope of the present disclosure.        
This disclosure introduces local-site transport (LST) methods and apparatuses for sampled payload signals. Each payload signal is an ordered series of samples. The payload signals are processed in successive “snippets,” where a snippet is a contiguous sub-series from the ordered series of samples comprising the signal. The methods and apparatuses disclosed herein are suitable for pulsatile signals and for digital signals. Band-limited analog signals may be sampled, such that they are also amenable to transport by the LSTs disclosed herein.
Video Signals
Video signals are used as examples of sampled payload signals for specificity where appropriate herein. There are many alternative, equally useful electronic formats for video signals. In any case, while images are two-dimensional objects, no matter what the color space of the electronic format and the resolution of each frame and the frame rate, every video signal is ultimately represented as a one-dimensional list of color values, i.e., an ordered series of input values. These input values are quantized for digital video and they are continuous values for pulsatile video.
Infrastructure Video LSTs
Mobile video systems are monolithic and compact, so LSTs are not a central focus of Mobile video equipment design. By contrast, LSTs are a critical design consideration for Infrastructure video systems, because Infrastructure video systems are assembled by end customers from equipment possibly made at various factories, and interconnected by difficult-to-predict and sometimes difficult-to-constrain infrastructure EM pathways.
An Infrastructure video LST conveys a video signal over an imperfect medium from the output terminal of a video sender, such as a camera or PlayStation, over an imperfect EM pathway to the input terminal of a video receiver, such as a display or Xbox. The sender and receiver may be implemented within a common enclosure, such as an all-in-one DVR with built-in display, or the two may be nearby, such as an HDMI display and a set-top box, or the two pieces of equipment may be located at different corners of a room, between fender and dash in a car, at opposite ends of a building, between buildings on a campus, or in different carriages along a train. LSTs for common media conveying electrical, RF, or optical signals represent the transported video as current/voltage, radio, or light, respectively.
An LST that can re-use legacy infrastructure cabling would be especially desirable, because cable installation is expensive, so reusing legacy infrastructure reduces installation costs. Such an LST is the subject of the present disclosure.
The following infrastructure LSTs are examples requiring a special kind of cable and connector:                EIA/CEA-861 (HDMI) is the LST for home entertainment. A set-top box sends video over HDMI cable to a Display.        USB Video Class is the LST for webcams. A webcam streams video over USB cable to a personal computer.        Ethernet is the LST for IP cameras. An IP camera streams video over Unshielded Twisted Pair (UTP) cable to a LAN switch.        
The following infrastructure LSTs are examples that do not require a special kind of cable and connector:                NTSC/PAL is the LST for legacy CCTV systems. CCTV cameras stream video over RG-59 coaxial cable to DVRs.        A wide range of HD CCTV LSTs is now available, including HD-SDI and several proprietary analogue HD solutions.        
A variety of LSTs is used for Virtual Reality (VR) systems that capture a person's appearances and gestures while contemporaneously presenting panoramic video.
Infrastructure video systems present a broad diversity of cabling challenges. In some infrastructure video applications such as CCTV, the EM pathway characteristics are not known when the individual equipment is manufactured. Some LSTs are therefore designed to tolerate a broad diversity of coaxial, UTP, and other cables.
DVI, LVDS, and HDBaseT are among the many HD video LSTs.
LSTs may be characterized by the specific set of limitations and trade-offs imposed. Unfortunately, the impacts of these limitations and trade-offs tend to increase as the number of infrastructure video equipment units and the resolution per video signal continue to increase in response to insatiable market demand.
SSDS-CDMA
In the search for an alternative LST, Spread Spectrum Direct Sequence—Code Division Multiple Access (SSDS-CDMA) transmission systems as defined in “Spread Spectrum Systems with Commercial Applications” by Robert C. Dixon, volume 3, Wiley & Sons 1994, is incorporated by reference into this specification.
SSDS is a signal transmission method in which each bit of the input signal is modulated by a higher-frequency Code in the transmitter, while the receiver correlates each sample of the received signal by a synchronized instance of the same Code.
SSDS is well known to confer multiple benefits, including resilience against EM propagation pathway defects, including for example roll-off, dispersion, reflections, and aggressor signals.
SSDS accounts for reflected waves from impedance discontinuities: the characteristic delay of these reflected waves is very much longer than a chip length. The only danger from reflections is locking on the reflected signal and not the main higher-intensity signal.
SSDS-CDMA is a transmission method combining several independent SSDS transmissions, through varying the Codes. The SSDS-CDMA receiver distinguishes among the various transmitters based on the Code used by each transmitter.
This disclosure addresses encoder assemblies and decoder assemblies adapted for use with arbitrarily impaired EM pathways.
An LST ideally delivers fit-for-purpose video. For human viewing applications of video systems, a fit-for-purpose LST delivers as faithful as possible a rendition of the payload video signal, while introducing a minimum of visually disturbing artifacts. The use of legacy cabling is always the least-cost cabling method, all else being equal, and fit-for-purpose LST can re-use legacy cabling, rather than requiring new or special cabling, and can utilize the full bandwidth and dynamic range of the cabling or other EM pathways in order to convey the essence of the video signals usefully over inexpensive cables.
In addition to the electrical ravages of roll-off, dispersion, reflections, and aggressor signals, factors such as incorrect termination, crimping under force, gnawing by rodents, and immersion in water mean that there are likely to be propagation errors over infrastructure cabling. Prior LSTs cause imperfections from EM pathway propagation to manifest as perceptually disturbing artifacts that can materially degrade the perceived value of sensory payloads. In order to mitigate the impacts on signal fidelity, these LSTs impose cable-length restrictions along with costly compression and filtering circuits, all of which constrain system implementations, while simultaneously limiting fidelity.